Pulverulent and water bearing explosive and process of producing the same

ABSTRACT

A PULVERULENT OR WATER BEARING EXPLOSIVE MIXTURE AND METHOD OF MAKING SAME COMPRISING MIXING 0 TO 20% BY WEIGHT OF WATER, 3 TO 6% BY WEIGHT OF LIQUID HYDROCARBONS, 50 TO 97% BY WEIGHT OF MIXED CRYSTALS PRODUCED BY CO-CRYSTALLIZATION OF AMMONIUM NITRATE AND POTASSIUM SALTS, IN A PREFERRED RATIO BY WEIGHT OF 20/1 TO 4/1, THE MIXED CRYSTALS HAVING A CRYSTAL FORM THAT IS ISOMORPHOUS WITH THE MONOCLINIC CRYSTAL FORM AN AMMONIUM NITRATE III, THE MIXED CRYSTALS HAVING A LOWER TEMPERATURE OF CRYSTAL FORM TRANSITION THAN 32.2*C., WHICH IS THE NORMAL LOWER TEMPERATURE OF TRANSITION OF PURE AMMONIUM NITRATE III, THE MIXED CRYSTALS BEING CRYSTALLIZED BETWEEN 100 AND 20*C. IN THE PRESENCE OF SALTS OF PRIMARY AMINO ALKANES, IN THE PREFERRED AMOUNT OF 0.2 TO 1.5% BY WEIGHT, HAVING CHAIN LENGTHS RANGING FROM C8 TO C18, AND THE MIXED CRYSTALS HAVING A LIPOPHILIC SURFACE CHARACTERISTIC, STABLE AT TEMPERATURES BELOW 32.2*C., ESPECIALLY BETWEEN -20 AND +20*C.

United States Patent 3,684,596 PULVERULENT AND WATER BEARING EX- PLOSIVE AND PROCESS OF PRODUCING THE SAME Marcel Vercautereu, Casilla 4244, Lima, Peru No Drawing. Filed May 1, 1970, Ser. No. 33,901 Claims priority, application Peru, Sept. 15, 1969, A 8,739/ 69 Int. Cl. C06b /00 U.S. Cl. 149-41 35 Claims ABSTRACT OF THE DISCLOSURE A pulverulent or water bearing explosive mixture and method of making same comprising mixing 0 to by weight of water, 3 to 6% by weight of liquid hydrocarbons, 50 to 97% by weight of mixed crystals produced by co-crystallization of ammonium nitrate and potassium salts, in a preferred ratio by weight of 20/1 to 4/1, the mixed crystals having a crystal form that is isomorphous with the monoclinic crystal form of ammonium nitrate III, the mixed crystals having a lower temperature of crystal form transition than 32.2 C., which is the normal lower temperature of transition of pure ammonium nitrate III, the mixed crystals being crystallized between 100- and 20 C. in the presence of salts of primary amino alkanes, in the preferred amount of 0.2 to 1.5% by weight, having chain lengths ranging from C to C and the mixed crystals having a lipophilic surface characteristic, stable at temperatures below 32.2 C., especially between -20 and +20 C.

The present invention relates to pulverulent and water bearing explosives and processes of producing the same.

In my U.S. Pat. No. 3,499,180, dated June 10, 1969, a process is described in which an ammonium nitrate with lipophilic surface characteristics is used for the fabrication of pulverulent or water-slurried blasting agents. This ammonium nitrate is crystallized between 90 and 20 C. in the presence of 0.2-1.0 percent by weight of salts of primary amino alkanes with a preferable chain length of C -C and in the simultaneous presence of 0.4-1.0 percent by weight of salts of amino alkanols. In this patent, it is expressly stated that to guarantee the lipophilic surface characteristics of this ammonium nitrate at ambient temperature, only the presence of salts of amino alkanols was absolutely necessary; that means that no lipophilic ammonium nitrate is able to exist at ambient temperature, when salts of amino alkanes are exclusively used.

The surface of this ammonium nitrate by adsorption of al-kylammonium-micells received the physical characteristic of a hydrocarbon chain, that means a hydrocarbon-loving or lipophilic property, whereby it was made possible that such a surface was able to hold liquid bydrocarbons in a thermodynamic stable manner by adsorption. This special lipophilic characteristic was the starting point for the production of blasting agents with increased detonation sensitivity, brisance and blasting performance.

It always remains a condition precedent that to preserve the lipophilic characteristic only consisted of the combination of amino alkanes-amino alkanols, and that in the absence of amino alkanols, the oil-loving property disappeared rapidly at ambient temperature. During the investigations from which said U.S. Pat. No. 3,499,180 resulted, the function of the amino alkanols was not completely cleared. Experimentally, its essential effect was constantly observed. It was presumed that both amine types were simultaneously adsorbed on the ammonium nitrate surface; also, there existed a suspicion that the adsorbed liquid crystalline layer was composed of an entirely complicated mixture consisting of alkylammonium salts, alkanolammonium salts, water, dissolved ammonium nitrate and other eventually present ions.

3,684,596 Patented Aug. 15, 1972 Later observations of the explosives according to the above-mentioned patent led to the definite conclusion that the lipophilic characteristic, during cooling, was stable only until about 15 C. in the case of the pulverulent dry explosives, and until about 20 C. in case of the water bearing blasting agents. By further falling temperatures, the lipophilic surface characteristic disappeared progressively, which fact can be identified in observing that the compositions began to recrystallize in a very coarse shape, and that the same compositions showed decantations of fuel oil and became insensitive to detonation.

It is an object of the present invention to produce pulverulent or water-slurried explosives, which are also based upon lipophilic crystal surface, but which are capable to keep their oil-loving characteristic down to very low temperatures; which explosives are preferably sensitized by means of liquid hydrocarbons and which do not necessarily require the presence of sensitive and brisant explosives or metallic powders to assure their complete detonation.

The considerations and the steps which led to the present invention may be resumed as follows:

In further connection with the conclusions of said patent, it is reasonable to consider that the voluminous stable adsorbed liquid-crystalline layer will slow down the transformation of crystal state III of the ammonium nitrate to crystal state IV, during cooling. The heat of transition of crystal state III to state IV of ammonium nitrate is exothermic, while the heat of desorption of the micells, as generally known, is always endothermic. According to the absolute values of both these heats, the crystal transformation will only occur partially, i.e. at a lower temperature than 32.2 C, which is the known lower transition temperature of pure ammonium nitrate III. If the absolute value of these heats is the same (or better still, if the absolute value of the positive heat of desorption is higher than the absolute value of the negative heat of crystal transformation), in such a case no transition of crystal form III to crystal form 1V should theoretically occur. Nevertheless, it has been experimentally found that the lower transformation temperature of lipophilic ammonium nitrate is displaced highest only until 15 C.

A similar phenomenon is notable at the upper temperature of transition of lipophilic ammonium nitrate, which is displaceable from 84 to C.

It can be experimentally demonstrated that the transformation temperature of lipophilic ammonium nitrate III according to said patent is actually displaced and that the annulation of the lipophilic surface characteristic takes place in the neighborhood of these modified temperatures. This led to the hypothesis that only crystal form III would be capable to adopt a lipophilic surface through adsorption of alkylammonium salts; that this after transition to crystal form IV, which process must be accompanied with a momentaneous desorption of the liquid crystalline layer; this last crystal form IV is not any more suitable for a transition in order to receive hydrocarbon-loving surfaces. As a further deduction, it was set forth that other crystal forms could exist, which external surfaces should have a still more perfect compatibility with the lipophilic adsorbate.

These preliminary ascertainments and hypothesis are the point of departure to the present invention to be described herein below whereby the basic idea consisted in investigating several modifications of the crystal form of ammonium nitrate and its compositions and mixtures with other salts, in order to establish the most favorable crystal form, capable to adopt the most stable lipophilic form.

The general and the patent literature has published a numerous quantity of papers about double salts and mixed crystals (solid solutions) between ammonium nitrate and other inorganic salts, mainly nitrates. All these double salts and mixed crystals possess exactly defined stabilities at given concentrations and temperatures. Their crystal state is often isomorphous With one of both components, sometimes completely different. The present inventor has prepared a large quantity of double salts and mixed crystals, whereby ammonium nitrate was always the main component. Regarding the double salts, the following cations were tried, whereby the anion was principally maintained unchanged as nitrate and halogenide: sodium, lead (II), lithium, magnesium, calcium, uranyl, thorium (IV), etc. Solid solutions in ammonium nitrate were prepared with the nitrates, halogenides, acetates, etc. of the following best-known cations: potassium, rubidium, caesium, thallium (H).

From all tests with double salts, it appeared that none of the examinated combinations showed a lipophilic surface characteristic in presence of salts of l-amino alkanes. In certain cases, especially the double salts with magnesium nitrate, a real retrogradation or deterioration of the lipophilic property with respect to pure ammonium nitrate was verified.

comparatively, the mixed crystals have the advantage that relatively low quantities of incorporated salts are sufficient to provoke important modifications of the crystal state. Solid solutions in very different proportions have been prepared, without success, with the nitrates, halogenides and organic salts of rubidium, caesium and thallium (II). It is to be observed that all the crystal forms of these mixed crystals, according to the respective concentrations, are either isomorphous with the corresponding Rb, Cs and T1 (11) -salts, or isomorphous with the modifications II and IV of ammonium nitrate; or, however, belong to completely different crystallization systems. The same observation is also valid for the case of the above considered double salts.

Only the mixed crystals between ammonium nitrate and potassium salts, preferably potassium nitrate, show a lipophilic surface characteristic in the presence of alkylammonium salts. These mixed crystals are also the only ones, whose crystal form at ambient temperature or at a lower temperature is isomorphous with ammonium nitrate III.

The reasons why the monoclinic crystal form of ammonium nitrate HI and the isomorphous crystal form of its solid solutions with potassium nitrate are the only ones which are appropriate to get a lipophilic surface characteristic, are according to the inventors observations, the following:

(1) The alkylammonium-ions exist within a saturated ammonium-plus-potassium nitrate solution in the form of very highly associated micells, in equilibrium with the total electrolyte solution. Furthermore, an eventual excess of alkylammonium-ions exists as highly concentrated micells, in equilibrium with the smallest quantities of the total electrolyte solution. The former alkylammonium-micells have to be considered as soluble and the latter as insoluble. Following modern theories, the dissolved micells have a lamellar configuration, in which each single alkylammonium-ion is disposed almost in parallel with respect to the other ions, in one or several layers; they simulate a crystalline-like structure in one plane and have a more or less pronounced disorder in the third dimension. These micells will be adsorbed in a most stable manner on such crystals which have an extended and smooth surface of similar or nearly similar dimensions as the crystal-like surface of these micells. The needleshaped acicular ammonium nitrate III and the modification which is provoked by the presence of potassium nitrate should comply with these conditions.

(2) Only in very concentrated electrolyte solutions the alkyl-ammonium salts are able to exist under form of soluble micells, this being an absolute necessity for the instantaneous formation of an adsorbate on the crystallizing mixed crystals. Saturated solutions between ammoniumand potassium-nitrate fulfill this condition.

To obtain the mixed crystals, almost all potassium salts are applicable, especially in water containing explosive compositions, where a metathetic reaction is quite feasible with formation of potassium nitrate. Potassium salts, Whose anions can have an unfavorable reaction with the alkylammonium-cation, must, of course, be excluded. To this group belong, for instance, potassium sulfocyanide (alkylammonium-sulfocyanide forms an insoluble liquid coacervate), potassium sulfate (alkylammonium sulfate has a much too low solubility), etc. Other potassium salts are applicable, but in certain cases not recommended; to that belong, for instance, potassium acetate (potassium acetate increases the pH of ammonium nitrate solutions, which causes a decrease of the solubility of the alkylammonium salts), potassium chloride and potassium fluoride (these salts may contract ternary and quaternary mixed crystals with ammonium nitrate, which are isomorphous with ammonium nitrate III, but whose crystals may have certain modified faces which are less suitable for a most stable adsorption of the micells).

The preferred potassium salt in the compositions according to the invention is potassium nitrate, because the presence of an excess of foreign-ions influences more or less the perfect crystal form of the pair ammonium nitrate-potassium nitrate.

The preferred percentage of potassium nitrate or other potassium salts lies at about 7%. The practical avantageous percentage fluctuates between 3 and 15% or, in other words, the ratio by weight ammonium nitrate/potassium nitrate should lie between the values of 20/1 and 4/1. By all means, higher amounts of potassium salts are, of course, applicable but not justified for the desired purpose. Lower quantities than 3% could be applied in cases where the temperature of storage and surroundings of the explosives should always remain relatively elevated.

The alkylammonium salts must be present under the most convenient form possible, in order to attain a most dense and stable adsorbate. As previously mentioned, the soluble alkylammonium salts are the ones which form the lipophilic micell layer on the mixed crystals; therefore, it is important to choose a sufliciently soluble salt avoiding, nevertheless, the use of an excessively soluble salt which would retrograde the maximum adsorption. Further on, a certain excess of undissolved alkylammonium salts (generally in the state of a gel) must always be present; in other words, a saturated solution of alkylammonium micells must constantly be provided. Under such circumstances, a spontaneous adsorption takes place on the surface of the mixed crystals, in which process the insoluble alkylammonium salt serves as a reservoir to compensate continuously the saturation of the soluble micellar phase. Pure n-octylammoniumand pure n-decylammonium-salts are not advantageously useable, due to their excessively high solubility; n-dodecylammonium salts approach a favorable solubility limit; higher alkylammonium salts possess a much too low solubility. In most cases, mixtures between C C and c -alkylamines are selected to attain the desired solubility. A mixture consisting of C to C n-alkylamines, commercially known as coco-amine, is also advantageously admixable.

The choice of the anion of the alkylammonium salts varies accordingly to the desired explosive type and/or sensitivity of detonation. In water bearing blasting agents the monovalent anions of the strongest inorganic acids are preferred, in the following order: perchlorate, chloride, nitrate. This order is in correspondence with the deceasing degree of dissociation of the respective acids. This phenomenon is explained as follows: The higher the degree of ionization of the alkylammonium salts, the harder will be the salting out through flocculation of the same in presence of an excess of electrolytes. In this way, it appears that the n-alkylammoniurn perchlorate micells are the most soluble, and that the n-alkylammoniumnitrate micells are the less soluble in this considered series,

wherefore the former will produce the most sensitive water containing blasting agents. This can experimentally be verified by means of the determination of the critical diameters for complete detonation of equivalent water containing blasting agents, in which only the anion of the alkylammonium salt has been varied: In case of perchlorate, the critical diameters lie at about 2 to 2.5 inches (SO-62.5 mm.) for chlorides, the critical diameters increase up to 2.5 to 3.5 inches (62.5-87.5 mm.); and when nitrates are set in, critical diameters stabilize at values of 3 to 4 inches (75-100 mm.). In pulverulent explosives, inorganic or organic best soluble alkylammonium salts are preferred, in such a way that the pH of the surrounding solution of the lipophilic mixed crystals is not higher in the finished product than the pH of pure ammoniumplus-potassium nitrate solutions, i.e. at about 6, since the free H-ions have a strong floccuating effect on the n-alkylammonium micells. Thus, if in this case inorganic salts are chosen, these should be formed in situ by means of acid salts, preferably zinc nitrate.

The preferred percentages of alkylammonium salts in the explosive mixtures fluctuate between 0.2 and 1.5%. Amounts higher than 1.5% are of no essential advantage. Lower quantities than 0.2% are not able to guarantee a suflicient lipophilization of the surface of the mixed crystals.

According to experience, it has been established that the most stable lipophilic surface of the mixed crystals comprises n-dodecylammonium salts, wherefore this amine will appear in all compositions, but seldom as the only one. Besides of the particularity to have guaranteed a monoclinic crystal surface, stable at low temperatures, by means of the salt pair ammonium nitrate-potassium nitrate, it appears that the solubility of the amines at these same low temperatures must also be kept always sufliciently high, preferably higher than the critical concentration for micell formation. This is attained by mixing n-dodecylamine with the lower C and C amines, which makes it simultaneously possible to lower the Kralft-temperature (temperature at which the critical concentration for micell formation commences), desirably to below 0 C.

Regarding the range of the higher temperatures, it is demonstrated that starting from 60-65 C. the solubility of the n-dodecylammonium salts (pure or mixed with the lower alkylammonium salts) commence to strongly increase in such a way that the afiinity of the micells is displaced towards the aqueous phase, and that a great diminution of the aggregation number becomes noticeable. This disadvantage is reduced or eliminated when the temperature of crystallization of the mixed crystals is lowered through addition of inorganic salts or organic substances. Sodium nitrate and calcium nitrate count among the most important and best-known substances which have the aforementioned property to increase the general salt solubility. By increasing the water contents of the pure ammonium-plus-potassium nitrate solution, the same effect is attained, but such an increase of the water contents for blasting in technical output reasons is many times not desirable. The preferred contents of these inorganic salts, which are able to increase the general solubility of the electrolytes, at constant water contents, lies between 4 and -8% by weight, which the water bearing slurried blasting agents concerns. For the production of the pulverulent explosives this first kind of salts, which enables the aforementioned increase of solubility, is preferably not used.

A second group of substances, which are capable of increasing still more the sensitivity of detonation of the water containing blasting agents, are such organic liquids, which are simultaneous solvents for alkylammonium salts and ammonium-plus-potassium nitrate. It has been found that formamide is the most important of these substances. It is remarkable that a 12.5 molal solution of ammonium nitrate in pure formamide, at 20 C., does not have a flocculating action upon simultaneously dissolved n-dodecylammonium-chloride, whereas, to the contrary, a 0.1 molal aqueous solution of ammonium nitrate has already a salting-out effect. Furthermore, it is to be mentioned that this great increase of solubility of the n-dodecylammonium salts does not cause a diminution of the micell aggregation number. Both of these factors contribute to assure a better lipophilization of the mixed crystals, by which mechanism it is made possible to produce water containing blasting agents, the critical diameter of which can be set down until 1.5 inches (37.5 mm.) and the minimum booster weight (initial explosive quantity) of which can be lowered until A lb. (38 gr.); (still further reduced diameters and smaller booster weights were not tested due to practical field execution reasons). Other organic substances, inclusive of crystallized compounds, have a similar effect as formamide; among them may be considered principally glycol and glycerine, dimethylformamide, urea, etc. Nevertheless, formamide is by far preferred, which, as herebefore explained, has the property of increasing the solubility of the alkylammomum salts in saturated electrolyte solutions at low tem peratures.

The very water soluble alkanolammonium salts, specially triethanolammonium nitrate and triethanolammonium acetate, which is a highly viscous fluid at room temperature, also belong to this group. Because of their ionic character, these salts will have their greatest efliciency as solvents for alkylammonium salts only in media of very low water contents. Therefore, the lower alkanol ammonium salts with alkyl chains of preferably 2 or 3 carbons find their application in the pulverulent explosives of the present invention.

The preferred contents of these compounds, which increase the solubility of the alkylammonium salts without decreasing the aggregation number of the micells, lies between 1 and 2% by weight, in case of the pulverulent explosives, and between 5 and 7% by Weight, in case it concerns water containing slurried blasting agents.

It follows from the foregoing exposition that the most important secondary component of the water bearing blasting agents according to the invention is formamide, because it produces simultaneously a descent of the saturation temperature of the hot ammonium-plus-potassium nitrate solution and an increase of the solubility of the alkylammonium salts at the lower temperatures, without provoking a degradation of the micellar complexes. Within the same development it must be further remarked that the secondary components of the first group, such as sodium nitrate and calcium nitrate, have also a certain solubility regulating function with respect to the alkylammonium micells at the low temperatures, since the solubility of the micells augments with increasing molality of the dissolved inorganic salts. The auxiliary components of the before considered first and second group have also a solubility regulating function, though in a lesser degree, at the low and high temperatures, respectively. In summary, the progress of the herein described invention comprises mainly, firstly, in the fact of substituting in the water containing slurried blasting agents for the alkanolammonium salts, which was proposed in my U.S. Pat. No. 3,449,180 by formamide or similar acting substances; and, as well as, secondly, in the novelty of making use of lipophilic mixed crystals instead of lipophilic ammonium nitrate, due to which it is not absolutely necessary to execute the crystallization of the lipophilic mixed crystals in the simultaneous presence of alkylammonium salts and of alkanolammonium salts or other alkylamine solubility increasing substances, in order to maintain the lipophilic surface characteristic at low temperatures. Nevertheless, as is to be understood from the foregoing exposure, the simultaneous use of l-amino alkanes and of the formerly defined substances is a preferred practice.

It should be observed here that such components as sodium nitrate, formamide, urea, etc. also appear in the composition of many conventional explosives (water bearing or not), wherefore the peculiar stabilization eifect of these substances must be accentuated in the compositions according to the invention. Particularly formamide has already been proposed for use in water slurried blasting agents, in order to attain or to improve the following characteristics: as a means to depress the freezing point; as a means to increase the energy and sensitivity of the aqueous phase; as a dispersionor solvent-medium for certain present components, such as, for instance, nitrocompounds. According to the foregoing description, it could be expressed that formamide in the compositions according to the invention sensibilizes indirectly the crystalline phase, because by an increase of the solubility of the n-alkylammonium micells, the lipophilic characteristic of the crystalline phase is reinforced. Furthermore, it results from examples 6.3.1 to 6.3.9, herein, that formamide has its maximum effect only within a narrow concentration range. At lower or higher concentrations than the optimum ones, the sensitivity of the corresponding explosive mixtures suffers a rapid retrogression, because the solubility of the n-alkylammonium micells in the respective solutions has not yet reached or already surpassed its optimum value. The optimum ratio by weight of water/ formamide lies between 2.5/1 and 3.5/1.

Other water soluble combustible materials are not recommended to be used in the compositions according to the present invention. Methanol and ethanol have a solubility-increasing effect on the alkylammonium salts, however with simultaneous and rapid reduction or of the aggregation number of the micells complexes.

Other additional components of these explosive mixtures are: barium nitrate, mostly up to 0.5%, to participate the disturbing polyvalent anions; zinc nitrate, up to 1% as pH regulator, if necessary, etc. Metallic powders, principally aluminum, may be admixed in a desired quantity in order to increase strength and brisance of the explosive mixtures. Water-swelling polymers are used to obtain the water resistance of the slurries. The chosen swelling polymers must be of non-ionic nature, or else a reaction occurs with the alkylammonium ions with loss of the lipophilic property of the mixed crystals. Guar flour and polyacrylamide were found to be the best appropriate swelling compounds; on the contrary, the anionic carboxylmethylcellulose, for instance, is by no means applicable. It appears that all incompatibilities between undesired impurities and the alkylammonium salts must be avoided. Such impurities consist in the first place of almost all polyvalent anions and are often carried along with the used raw materials. For instance, Chile saltpeter contains,

among other impurities, about 0.5% sulfate ions. Likely,

certain ammonium nitrate qualities may contain 0.1 to 0.3% sulfate ions; especially prepared qualities of guar flour may hold varying percentages of borate-, chromate-, antimoniateetc. ions. Such guar qualities should not be used; the use of guar flour should be limited to the pure quality or to the so-called self-complexing kind. The formerly mentioned sulfate ions can generally not be avoided; they are easy to eliminate through addition of an equivalent quantity of a barium salt, which precipitates at the same time most of the other polyvalent anions. Certain technical ammonium nitrate qualities contain surface active substances used as anticaking agents. The use of such an ammonium nitrate should be avoided, even if the surface active anti-caking agent is a primary aliphatic amine, in order to not originate uncontrollable interferences. If the anti-caking agent would be of an anionic nature, in that case the use of a so treated ammonium nitrate is absolutely prohibitive. The same observation holds for sodiumand potassium-nitrate. The higher aliphatic alcohols, starting from propanol, provoke a complete decantation of the alkylammonium salts as liquid coacervates, and the higher aliphatic acids combine as unsoluble compounds. To produce the lipophilic mixed crystals it is parted from a hot solution, which is mostly saturated at a temperature of 60 to 100 C. At a temperature higher than C., imperfect lipophilic mixed crystals are obtained or none at all, for the same reason as has been explained herein in the introduction: Subject to the contents of potassium nitrate and at temperatures above 84 C., which is the established upper temperature of transition of crystal form III of pure ammonium nitrate, mixed crystals are still obtained, which are isomorphous with ammonium nitrate III; at still higher temperatures and subject to the potassium nitrate contents, an non-lipophilic crystal form, isomorphous with ammonium nitrate II or with potassium nitrate, is formed; above C. no lipophilic crystals will form anymore. Preferably a maximum temperature of 100 C. should not be exceeded in production processes of dry pulverulent explosives. In production processes of water containing blasting agents, a maximum starting temperature of 60 to 65 C. is recommended.

The hot starting solutions for crystallization comprises water, ammonium nitrate, potassium nitrate, eventually alcaline or earth-alcaline nitrates, formamide or other Water soluble facultative components and alkylammonium salts (as such as salified in situ). The crystallization of the lipophilic mixed crystals can be carried out by means of generally known devices and methods; in spite of the fact that an evaporation of saturated solutions at constant temperature and at sub-atmospheric pressure is preferrerd. It is not indispensable to produce completely dry mixed crystals; a remaining humidity of 12% does not unfavourably affect the quality of the corresponding pulverulent explosives.

The composition of the lipophilic mixed crystals lies preferably within the following limits: 82 to 95% by weight of ammonium nitrate; 3 to 15% by weight of potassium nitrate; 0.2 to 0.5 by weight of alkylammonium salts; and, 1 to 2% by weight of triethanolammonium salts, with a final humidity of 0.2 to 1% by weight.

As a sensitizer of the lipophilic mixed crystals, the commercially available derivatives of mineral oil are preferred, principally fuel oil. The chain length of the preferred hydrocarbons comprises about 12 carbons. Linear or ramified aliphatic hydrocarcarbons, as well as cyclic or aromatic hydrocarbons are equally applicable.

Brisant high explosives, such as nitroglycerine, trinitrotoluene, starch-nitrate, pentaerythrite-tetranitrate, sugarnitrates, etc. may also be admixed in desired amounts. Nevertheless, in this invention their traditional functional as a sensitizer has been substituted by the lipophilic mixed crystals, which makes their presence not absolutely necessary. As a further object the present invention consists in producing economical and safe-to-handle explosives, the application of bn'sant high explosives is not recommended. In the same way, metallic powders, principally aluminum powder, is not necessary to sensitize the explosive mixtures. Nevertheless, these metallic powders are advantageously admixed to increase strength and brisance in cases where such as increase is desired.

The preferred pulverulent explosive mixtures consist mostly of 84 to 97% by weight of lipophilic mixed crystals, 3 to 6% by weight of diesel oil (fuel oil No. 4, according to the American ASTM clasisfication) and 0 to 15% by weight of metallic powders, preferably aluminum. These pulverulent explosives are of extraordinary strength and brisance; they may be packed in cartridges of small diameters, e.g. A; inch (72 mm.), and they are sensitive to detonation with a blasting cap No. 6. The manner of handling of the cartridges is not different from the conventional ammoniacal dynamites. The pulverulent explosives, according to the present invention, may also be packed in bags in order to be poured loose into the bore holes.

The slurried water containing explosives may be produced in two different ways: Firstly, use can be made of the dry lipophilic mixed crystals, as formerly described, which are introduced in an at room temperature saturated electrolyte solution, together with diesel oil and other desired components. The electrolyte solution should at least contain ammonium nitrate, a potassium salt, and an alkylammonium salt; other desired soluble secondary components may be added. Nevertheless, the preferred 10 livery truck is recommended to pump the fresh explosive with a temperature of 2.0-30 C. into the bore holes. A subsequent solidification of the explosive within the bore hole is of no importance.

method to produce the slurries comprises simply in cool- By means of the following examples the invention will ing a hot saturated solution down to 2040 C., wherebe exemplified: Examples 1 to 4 illustrate the theoretical after diesel oil, guar rflour, aluminum powder, etc. are basis of the invention. Example 5 describes a few typical admixed, without separating the mother liquor. methods of preparation of water containing explosives The preferred compositions of water bearing slurried according to the invention; and Example 6 resumes the blasting agents fluctuate mostly within following limits 10 characteristics of same. Example 7 gives a few methods (all percents are percents by weight): 12 to 20% of to prepare lipophilic mixed crystals which can be used water; 50 to 70% of ammonium nitrate; 3 to 15% of as raw materials for the elaboration of the pulverulent potassium nitrate (or partially another potassium salt); explosives of Example 8. 4 to 15% of secondary substance (being the sum of so- EXAMPLE 1 dium nitrate, calcium nitrate, barium nitrate, formamide, 15 urea, etc.); 0.4 to 1.5% of alkylammonium salts; 0 to The solid solutions between potassium nitrate and amof aluminum powder (or another metallic powder); monium nitrate have been principally and intensively 3 to 6% f di l i1 (f l n N 2, according t th investigated by Prof. Dr. E. Jaenecke of the former I. G. American ASTM classification); and, 0 to 0.7% of a Fal'henilldllstrie y)- everal mpositions water swelling colloid or polymer (guar flou 1- poly- 20 of mixed crystals have been repeated by the inventor with acrylamide). In certain compositions small amounts f the variation that crystallization was carried out in presother combustible materials are also admixed, such as enee 0f ll-alkylammohium chloride The P tage Of carbon, asphalt powder, etc. Brisant high explosives are, nylammonium chloride plus n-octylammonium of course, also applicable; nevertheless (as in the case chloride was p constant at in all Preparations, of the pulverulent explosives) they are not necessary to wherein the eciprocal proportion between C and C sensitize the blasting agent. was constantly decreased with falling temperature ac- The water containing blasting agents are pack d i cording to the conclusions of Example 3. In all preparaplastic bags or may be directly bulk loaded in the drill tioirls, the q y of Water nd f ammon um nitrate holes by means of a delivery truck. The advantages of was p ant t 15, and 6 6 g., respectively. In Exthese new slurries consist in an excellent sensitivity to ample the Variation consists in adding Varying detonation in small diameters (bore holes), and in the quantities of potassium nitrate; in Example 1.2, varying need of but a very small booster weight (initial exploamounts of potassiumand Sodium-nitrate Were pp sive quantity) for their complete detonation. Detonation lIIl eaeh Case a Saturated ut Was prepared at 60 t0 sensitivity is insured down to a critical cartridge-or bore 0 C-, which was subsequently cooled under agitation hole diameter of 1.5 inches (37.5 mm.) in case of special by h in p Water, dOWIl to 3 C-, Whereafter, a d compositions as described above, and up to the critical Without separation of the mother liquor, the samples loading density of 1.55 gr./cm. comparatively, these w e Stored during 48 hours at varying temperatures. figures reach the values of 5 inches (125 mm), respec- The progressively changing temperatures were of 20, 15, tively, 1.20 gr./cm. for the slurries of US. Pat. No. 10, 5, 0, 5, -10, --l5, and -20 C. One and the same 3,449,180. A further characteristic of the slurries accordsample was exposed to a gradually descending temperaing to the present invention concerns their unusual air ture, until a de-lipophilization of the crystals could be gap sensitivity, which can go up to 12 inches (30 cm.) verified, which in the present case was easy to demonfor charges of 6.5 inches (162.5 mm.) diameter loadings. strate by the fact of a modification of the crystal size These characteristics, which have not yet been known, towards a coarse unevenly shaped form (microscopically are the best insurance for a complete detonation of these or, in many typical cases, visually appreciable). An addinew water containing blasting agents. tional method to recognize the de-lipophilization com- Finally, it must again be emphasized that the slurries prises mixing the presumably transformed crystal mass according to the invention are fully usable at very low (plus mother liquor) with fuel oil, whereby a rapid defield or operating temperatures, beneath 0 C., which cantation of the oil is observable. Before transformation was until now very problematic for what the slurries of of the crystals takes place, it is clear that no oil decantaof the prior art concerns, inclusive of such slurries which tion occurs. The de-lipophilization of the mixed crysare sensitized by means of brisant explosives. In this contals cannot sharply be established but appears progressnection it is to be observed that the water bearing explosively. In the following tables two different temperatures sives according to the present invention begin to lose their are considered: T =upper temperature, at which a de fluidity at 10 C. and that beneath 0 C. they transform lipophilization is not yet observable; T =lower temperain tough semi-solid masses, which makes difiicult the ture. at which no lipophilic mixed crystals are present loading operation in the bore holes. For this reason and anymore. The difference between T and T is kept conin case of very low field temperatures, the use of a destant at 5 C.

EXAMPLE 1.1

Composition of solution (g.)

C12H25NH1C1/ PreparationNo. H20 NHtNot CaHnNHaCl KNO; T100.) T2( 0.)

EXAMPLE 1.2

Composition of solution (g.)

It is interesting to notice how the temperatures of delipophilization of the foregoing tables approach Dr. Iaeueckes temperatures of crystal transition, which proves that only a crystal form, which is isomorphous with the monocliuic ammonium nitrate III, is able to adopt a lipophilic surface characteristic by means of absorption of alkylammonium micells.

EXAMPLE 2 Again a certain number of solutions is prepared consisting of 15 g. of water, 66 g. of ammonium nitrate, 0.5 g. of n-dodecylammonium-chloride plus-n-octaylammonium-chloride and 4.5 g. of a varying potassium salt according to the following table. Each saturated solution is cooled down to 30 C., whereafter each sample is exposed to the progressively varying temperature cycle, as in Example 1, in order to determine in each case the temperatures T and T Potassium salt T1 0.) T2 C Potassium nitrate 15 10 Potassium fluoride- 5 Potassium chlorlde 5 Potassium bromide 10 Potassium iodide- 15 Potassium formiate 10 5 Potassium acetate- 15 10 Potassium cltrate 15 10 Potassium oxalate 15 10 Potassium biehromate 20 15 Comparatively with Example 1, higher or lower temperatures of de-lipophilization are found for the foregoing preparations; for the case of the higher temperatures the reason is to be found in the fact that the considered anion diminishes excessively the solubility or provokes the complete precipitation of the n-alkylammonium-cation, notwithstanding that a crystal form transition of the mixed crystals has not yet necessarily taken place. Regarding the lower temperatures, the explanation is more complicated: The presence of certain anions (chloride, fluoride) facilitates the formation of ternary or quarternary mixed crystals, which are also isomorphous with the crystal form of ammonium nitrate -III, but which has a still lower transition temperatre. Nevertheless, this isomorphism may have unfavorable undefined forms, from which certain disadvantages, in contrast with potassium nitrate, may result.

EXAMPLE 3 Several simultaneously saturated solutions consistnig of ammonium nitrate, sodium nitrate, and potassium nitrate are prepared at temperatures of 30, 20, 10, 0, 10 C. To each sample, which contains 15 g. of water, 0.5% by weight of n-alkylammonium-chloride is added, whereby the relation between C and C is changed. All samples are stored in a thermostatic chamber, wherein temperature is progressively regulated at 30, 20, 10, 0, and l0 C. The samples are observed after each course of 2 hours. In case a crystallization of mixed crystals occurs, before a flocculation or a crystallization of the n-alkylammonium salts takes place, the respective samples are eliminated and substituted by other ones, the saturation temperature of the inorganic salts of which is a lower one. At the occasion of each check at a de fined cooling temperature, all such samples are removed which show a flocculation or a crystallization of the nalkylammonium salts. The solutions are slowly warmed up again under constant and intensive agitation with a thermometer, during which operation a gradual re-dissolution of the precipitated matter is visible. The temperature at which a complete dissolution occurs is checked (a slight residual turbidity is almost always visible, which is originated by a separate gelatinous phase). In this way the temperature of saturation of the co-dissolved n-alkylammonium salts is established as follows:

Proportion by weight of Tempera- CnHtsNHaCl/ ture of C H11N H 01 saturation, No. =t=1 O.

For each considered case it has been determined in in this example the temperature at which a decrease of solubility of the n-alkylammonium salts begins. Other similar series may be executed, in which the nature and the amount of the n-alkylammonium-cations and their anions are varied, and in which the secondary components of the inorganic electrolyte solution are modified.

In Example 4, the application of the present example will be described.

EXAMPLE 4 In Example 1 it was explained, which the proportion between ammoniumand potassium-nitrate must be, in order to orginate mixed crystals at an established temperature, the crystal form of which is isomorphous with the crystal form of the monoclinic ammonium nitrate III, which mixed crystals are able to adopt a lipophilic surface characteristic. A second condition for attaining this property is that the dissolved n-alkylammonium micells, at the aforementioned established temperature, are always sufiiciently soluble and do not crystallize with destruction (or dilution) of the lipophilic surface. To fulfill this condition, the necessary data are given in Example 3.

Combining the conclusion of Examples 1 and 3 it is possible to foresee, and even to "calculate, the minimum temperature for maximum detonation ability (MTMD).

Being, for instance, provided that a water containing explosive composition is needed with a MTMD of 15 C.; on combining Examples 1.2.4 and 3.3, the following composition is obtained: 15 parts of water; 66 parts of ammonium nitrate; 4.5 parts of potassium nitrate; 7.5 parts of sodium nitrate; 0.4 part of n-dodecylammoniumchloride; and 0.1 part of n-octylammonium-chloride. Hereto a quantity of e.g., 5 parts of fuel oil Nr. 2 can be mixed for sensitizing, as well as e.g., 0.5 part of guar flour. (All figures are parts by weight.)

A second example consists in combining Examples 1.1.11 and 3.7 to obtain a water containing explosive with a MTMD of 0 (3.; 15 parts of water; 66 parts of am- 13 monium nitrate, 9 parts of potassium nitrate, 0.2 parts of n-dodecylammonium-chloride, and 0.3 part of n-octylammonium-chloride. This mixture can, e.g., be used with 3.5 parts of fuel oil Nr. 2, 0.75 of polyacrylamide, and 20 of aluminum powder. (All figures are parts by weight.)

These theoretical explosive compositions were treated by means of practical trails, whereafter the following was verified:

(a) At the MTMD the maximum characteristics of the explosive are still conserved.

(b) The detonation of the explosives is also still possible at lower temperatures, generally at 5 to 10 C. below the MTMD which corresponds to the amine composition, because at these low temperatures the solubility of the n-alkylammonium micells gets very small, but does not reach a zero value.

With reference to the MTMD which corresponds to the composition of the mixed crystals, the minimum temperature must be strictly observed.

If a water containing explosive is detonated at a temperature below its theoretical MTMD, a retrogression of its characteristics occurs rapidly, until its insensitivity is reached: Decrease of the critical density of the explosive; increase of the critical bore hole diameter; and increase of the critical booster weight. Such a retrogression occurs, for instance, when Examples 1.2.7 and 3.5 are combined, under the supposition that the MTMD would be 0 C.

Nevertheless, in presence of about 6 parts by weight of formamide, the MTMD subject to the amine composition may be lowered by 10 to 15 C., without provoking a substantial loss of the blasting performances.

EXAMPLE A few methods of preparation of water containing blasting agents according to the invention will be described as follows:

Example 5.1

Into a heatable, insulated agitating container of a capacity of 1.200 liters, a quantity of 790 kgs. is pumped of a technically pure ammonium nitrate solution containing 14.9% of water and having a temperature of 85 C. Afterwards, 60 kg. of sodium nitrate and 65 kg. of potassium nitrate, both of synthetical quality, are dissolved. Into a separate container of a capacity of 20 liters, a quantity of kg. of water is weighed, whereto 3 kg. of hydrochloric acid at 36.5% is admixed. Subsequently, while agitating, 3.7 kg. n-dodecylamine and 1.3 kg. n-octylamine are added to this acid solution. The pH of the so obtained n-alkylammonium-chloride solution is regulated at a value of 55 .5, adding small quantities of amines or acid, if necessary. This n-alkylammonium-chloride solution, together with 20 kg. of water, are admixed to the foregoing electrolyte solution. The so obtained total solution is introduced into a mixer provided with a cooling jacket. The jacket is fed with water of 20 C., and the solution is cooled so long until a temperature of 30 C. is reached. Meanwhile, a suspension comprising of 44 kg. of fuel oil Nr. 2 and 3 kg. of guar flour is prepared within a pressurized tank with a capacity of 75 liters. The suspension is mixed and maintained homogeneous by means of compressed air. This suspension is injected into the lower part of the cooler by means of compressed air and homogeneously mixed with the cooled pasty mass. A slurry is obtained, which is packed in polyethylene bags.

Example 5.2

Into the same heatable, insulated agitating container the following ingredients are mixed and heated up to 68 C.: 160 kg. of water; 670 kg. of ammonium nitrate (with :1

contents of 0.16% ammonium sulfate); 5 kg. of barium on until complete homogeneity; the pH is regulated as before at a value of 5.8-6. The total solution is continuously pumped through a thin layer heat exchanger, the cooling jacket of which is fed with water of 18 C. A quantity of 475.1 kg. of the cooled slurry is received at 22 C. in a mixer, whereafter the emerging slurry is branched out into a twin mixer. To the collected charge of 475 .1 kg., 20 kg. of fuel oil Nr. 2 and a suspension consisting of 2.4 kg. of polyacrylamide and 2.5 kg. fuel oil Nr. 2 is homogeneously admixed. A water containing blasting agent is obtained, which can be packed in polyethylene bags or which can be filled into a tank-truck to be directly delivered into the bore holes of an open pit mine.

Example 5.3

Into the twin mixer of foregoing Example 5.2, a quantity of 402.5 kg. cooled slurry is collected. kg. of a medium-fine aluminum powder of a purity of 99.8% and 12 kg. of fuel oil Nr. 2 are added, together with a suspension comprising 3 kg. of glycol and 2.5 kg. of selfcomplexing guar flour. After homogenizing, a slurry with extraordinary strength and brisance is obtained, which, e.g., is able to assure an extraordinarily favorable fragmentation of a hard and tough magnetite ore.

Example 5.4

In a heatable, insulated agitating container, a solution with 65 C. is prepared, comprising 170 kg. of water, 635 kg. of ammonium nitrate (with a contents of 0.10% ammonium sulfate), 3 kg. of barium perchlorate and 83 kg. of synthetic potassium nitrate. Separately, the n-alkylammonium salts are prepared as follows: (1) To a quantity of 40 kg. of formamide, 3.15 kg. of perchloric acid at 70% are admixed for the salifying with 4 kg. of n-dodecylamine. (2) In the same Way, to 20 kg. of formamide 4.45 kg. of perchloric acid of 70% and, respectively, 4 kg. of n-octylamine are admixed. In both cases the pH is regulated at a value of 5-5.5. To the first-mentioned elec' trolyte solution the formamide-containing n-dodecylammonium-perchlorate solution is admixed, whereafter the total solution is continuously pumped through a thin layer heat exchanger, the cooling jacket of which is fed with water of 18 C. The rate of flow of the solution is controlled in such a Way, that a cooled mother liquor-pluscrystals is obtained with a temperature of 30 C. This paste is collected in a mixer and homogeneously mixed with the formamide containing n-octylammonium perchlorate solution. Mixing is carried on with a suspension comprising 30 kg. of fuel oil Nr. 2 and 3.4 kg. of polyacrylamide. A water containing slurry results, which is especially suitable to be used at very low temperatures, below 0 C.

Example 5.5

In a heatable, insulated agitating container a solution with 60 C. is prepared, comprising 165 kg. of water, 650 kg. of ammonium nitrate, 40 kg. of sodium nitrate, 3.65 kg. of barium nitrate, 75 kg. of potassium nitrate, 4.35 kg. of hydrochloric acid at 36.5%, 4.5 kg. of n-dodecylamine, and 2.5 kg. of n-octylamine and 55 kg. of formamide. The pH is regulated at a value of 5.8-6.0. The solution is cooled down at 21 C. by means of a continuous thin layer heat exchanger. A quantity of 500 kg. of the cooled slurry is collected in a mixer, where to 60 kg. of medium-fine aluminum powder (99.9% 5 kg. of milled carbon, 15 kg. of fuel oil Nr. 4, and 4 kg. of polyacrylamide are admixed.

Example 5.6

In a heatable, insulated agitating container a solution with 25 C. is prepared, comprising 75 kg. of water, 30 kg. of formamide, kg. of ammonium nitrate, 2 kg. of barium nitrate, 20 kg. of potassium nitrate, 0.85 kg. of hydrochloric acid at 36.5%, 1 kg. of n-dodecylamine. This solution is pumped into a mixing device, whereafter 203 kg. of lipophilic mixed crystals are admixed which 15 were obtained (according to Example 7.1) with a humidity of 1.2% by weight. Finally a suspension is added which comprises 20 kg. of fuel oil Nr. 2 and 2.65 kg. of polyacrylamide, and mixing is carried on until complete homogeneity. By this method a slurry is obtained which 16 brisant high explosives were created, and whereby the critical diameter of same is reduced about /2 to 1 inch The critical density of these compositions, i.e., their maximum density, which still allows a complete detonais specially liquid and appropriated for application of the tion of the charge, is found to lie between 1.15 and 1.55 well-known mixing-and-loading system with a distribution and depends on the diameter of the charge, on the field truck in the vicinity of the bore holes of the mine. temperatures and on the explosive composition.

The critical booster quantity, i.e. the minimum quantity EXAMPLE 6 10 0f the priming explosive, which is necessary to guarantee a complete detonation, also depends upon these three Accordmg to the PrFparatlon m d of Example conditions and varies between and 1 1b. (38 and 450 several water containing explosive mixtures were prepared which are detfliled in tables- In all For comparison it should be reminded that the water Preparatlons a techmcal ammQmUm filtrate Wlth a 15 bearing explosives according to US. Pat. No. 3,449,180 of 012F045 of ammcfmum sulfate used- The retain their complete capacity with falling temperatures utilized sodium nitrate was in all cases Chile salt-peter, only down to C h ft a rapid insensitivity to and potassium nitrate was of a synthetical quality. All detonation nccum the inorganic alkylammonium salts had been prepared previously according to the described methods, whereby 20 TABLE 6.1 the starting bases were commercially available alkyl- Composition amines and acids. All the other secondary and additional components were of customary commercial quality. The applied swelling compounds correspond to the following Percent by weight: 65 2a 22 28 52-6 36 52s rnmom l ra 0.. Guar flour (1): Trademark MDC of Messrs. Stein gggifii fi iiig i- I 3 28 Hall, New YQrk. 1Z3LTlllTItnil'flg6::-: 8.38

e, a Guar flour (2): Self-complexing guar flour EXFC-SO Hydrochloric acid, 36.57 of Steln Hall York' 30 Perchlorie aeid,70%. i 0.40 0.40 0.40 Polyacrylamide (3): Q ality superfloc 84 of Mess n-Dodecylamine 0.45 0.45 0.45 0. 45 0.45 0.45 American Cynamid, New Jersey. l' g q g g 22g 22g 223 2% 23 9-28 1.16 01 0. The employed aluminum powder was the 99.8% pure gmfifgaw z Q32 Q30 commercial quality SA-22 of Messrs. Alcan, Canada. 99.8% a 1000 20.00 From Table 6.1 the influence of the selected alkyl- 30 3532}???gfgg g ifig a" A 4 3% 2/5 2% 2 ammonium salt on the blasting characteristics is made (fo charges oifiinc 5,500 5.600 5,600 5.750 5.400 0 Visible l ehar es oi5in0l1es a g Table 6.2 illustrates how an increasing water contents qx g h unfl nh- 4 4 5 5 is conducting towards a progressive detonation insen- 40 n g %;%f 6 6 8 1n sitivity.

Table 6.3 demonstrates in which way the presence of TABLE 62 formamide improves the detonation sensitivity and simultaneously explains the influence of falling field tempera- Composltmn tures. 6.2.1 6.2.2 6.2.3 6.2.4 6.2.5 6.2.6

Table 6.4 comprises an illustrative series of composi- Percent by weight: tions according to the present invention. Water 12.00 14.00 16.00 18.00 20.00 22.00 Regarding these examples it is to be Observed that fiifitlt itiiiiiiti:::: 2:88 3:83 2:38 21% i188 2338 intentionally no use was made of self-explosives, for 1S30dium nig age 5.1 13 Egg 3% 3% 5% .0

81111111 1'11 1'2. 8 better illustration of the preferred compositions, although Hyd,.0ch1onc acid,36 5% n28 n28 028 (L28 (L28 Q28 such a use would be absolutely possible, and whereby, n-Dodeeylamine 0.45 0.45 0.45 0.45 0.45 0.45 however, the economical advantages of the preferred 21 23 212 2 33 2:23 $28 blasting agents are moved into the background. Gum flour 0.3 0.3 Crit ldiarneteninehe 3 3 3 5 To all the compositions of the four tables, 10-20% m s A 6 nd by weight of aluminum powder can be added, whereby TABLE 6.3

Composition No.

. 15. 00 15. 00 i5. 00 15. 00 15. 00 15. 00 15.00 68.00 67.00 66.50 67.50 66.50 66.00 65.00 7. 00 7.00 7.00 9.00 9.00 9.00 9. 00 "-58 2'38 25* 2'38 238 2'38 8-88 n-Dodeeylammomum perchlor 0. 0. 60 0. 60 0. 60 0. 60 0 60 60 0. 60 ii-oetylarnnioriium perchlorate. 0. 15 0. 15 0. 15 0. 15 0.30 0.30 0. 30 0.30 Fuel oil No.2 3.00 3.00 3. 00 2.50 a. 50 3.50 3. 00 3.00 Polyaerylamide 3) 0. 0. 75 0.75 0.75 0.60 0. 60 0. 60 0. 60 Critical diameter at:

20 0., inches. 3 2 1% 3 3 2 1% 2 10 C.,inehes- 3 2 2 3 3 2 1% 2 0 C., inches.-. n.d. n.d. n.d. n.d. 4 3 2 2 10 0., inches-- n.d. n.d. n.d. n.d. 18 0., inches Nora-n.d. =non-detonable.

The preparations 6.3.1 to 6.3.9 were cooled down to 35 C. and then stored at progressively falling temperatures of 20, The preparations 6.8.10 to 6.3.12 were cooled down to 28 C. to be stored immediately at 10 C. and afterwards at -18 All shots were made-after storage of 48 hours-the soonest possible at the established temperatures to avoid a gain of temperature of the samples.

TABLE 6.4

Composition N o.

Percent by weight:

Watm- I 15.00 15. 00 15. 00 15.00 15.00 15. 00 15. 00 15. 00 15. 00 15.00

Ammonium nitrate 67. 90 66.60 66.40 66. 00 67. 10 68. 62. 40 65. 40 65. 67. 50

Potassium nitrate 5.00 9.00 5.00 7.00 7.00 6. 00 5. 00 9. 00 7. 00

Potassium chloride 00 Sodium nitrate 7.

Calcium nitratn Barium nitrate 0.

Fnrmamirle A onfamirio Glyml Carbon Srizar Coco-amine-perchlorate Coco-amine-chloride n-Dodecylammonium chloriden-Decylammonium chloride n-Octylanunonium chlori 2-ethyl-l-hexylammonium Phlnridn Guar flour 0.30 Guar flour (2)- Polyacrylarm'de (3) Critical diameter (at 10 0.), inches 5 4 EXAMPLE 7 Some preparation methods for the lipophilic mixed crystals applied for the pulverulent and water containing explosives according to the invention are described as follows:

Example 7.1

In an industrial vacuum evaporating device with a capacity of 1000 liters and equipped with a heating jacket and an agitator, solution is prepared comprising 100 liters of water, 510 kg. of ammonium. nitrate plus 70 kg. of potassium nitrate and 3.7 kg. of zinc nitrate hexahydrate, which is warmed up to 85 C. In a separate container of 10 liters capacity, 1.5 kg. of coco-amine and 6 kg. of triethanolamine are homogeneously mixed. The aminemixture is added to the foregoing electrolyte solution, as well as 10 g. of silicon oil as anti-foaming agent. Agitation is continued until complete homogeneity.

The heating jacket of the evaporator is regulated at 8385 C. and a vacuum of 60-25 torr is maintained during 2.5 to 3.5 hours. The obtained lipophilic mixed crystals, which at the moment of discharge have a temperature of 55-65 C., are packed in bags.

Example 7.2

In the same vacuum evaporating device, a solution is now prepared comprises 100 kg. of water, 570 kg. of ammonium nitrate, 30 kg. of potassium nitrate, 2 kg. of coco-amine-acetate and 10 g. of silicon oil. The evaporation of the water takes place under the same conditions as in case of Example 7.1.

Example 7.3

In a container of 10 liters capacity, 0.7 kg. of hydrochloric acid at 36.5% is admixed to 5 liters of water, whereafter 1.3 kg. of molten n-dodecylamine is added. This mixture is homogenized and, if necessary, smaller quantities of acid or amine are added for the purpose to obtain a final pH value of 5 to 5.5. During this salification of the amines, the temperature rises only up to approximately 45 C., wherefore a forced cooling is not necessary.

Separately, a solution that comprises 90 liters of water, 560 kg. of ammonium nitrate and 65 kg. of potassium nitrate is prepared in the vacuum evaporator; the n-dodecylammonium chloride solution and 10 g. of silicon oil are homogeneously admixed to the hot solution. The evaporation of the water takes place under the same condition as in case of method 7.1.

Further variations In other preparations, according to methods 7.1, 7.2 and 7.3, modifications of composition are introduced,

wherein the percentages by weight of potassium nitrate, n-alkylamine salt and triethanolamine, as well as the nature of the amine salts and the humidity of the final product are varied. All these preparations are reserved for the production of the dilferent explosive mixtures of Example 8.

EXAMPLE 8 According to the method described in Example 7.1 several charges of lipophilic mixed crystals were prepared in changing compositions and contents of humidity. After resting time of 24 hours, 94.5 parts of weight of lipophilic mixed crystals were blended with 5.5 parts by weight of fuel oil Nr. 4. Different explosives of the below indicated composition were obtained. The explosives were filled into cartridges of 22.0 mm. and 28.0 mm. diameter and stored during 3 months at a room temperature which fluctuated from 13 to 19 C., whereafter the explosion characteristics are determined. (All shots were set 01f by means of an aluminum blasting cap Nr. 6 of brand Briska.)

Examples 8.1.1 and 8.1.2 are intended to recall the prior art: Example 8.1.1 is simply based on an adsorption of n-alkylamine on pure ammonium nitrate which, as already known, is unable to produce cap-sensitive ammonium nitrate-fuel oil explosives at room temperature: Example 8.1.2 corresponds to the status of Pat. No. 3,449,180. Examples 8.1.3 to 8.1.6 describe compositions according to the present invention, which are based on lipophilic mixed crystals, in absence of secondary auxiliary substances. Examples 8.1.7 to 8.1.11 correspond to other compositions according to the invention, wherein the addition of an auxiliary substance enhances the sensitivity of the explosive mixtures. In all these examples, and for reason of comparison, only one triethanolammonium salt was chosen. In Example 8.1.12 an inorganic n-alkylammonium salt was applied, whereby, as noticeable, less sensitive ammonium nitrate-fuel oil explosives can be obtained (being in this case the pH of the aqueous medium of a considerably lower value, a fact which shifts the affinity of the micells towards this aqueous phase).

Futrhermore, it is observed that the presence of potassium nitrate does not cause a substantial loss of strength, but that it results in an interesting increase of brisance. A rising percentage of humidity causes a gradual decay of the blasting characteristics. In these pulverulent explosives, and subject to the kind of composition, a water contents of up to about 3% represents a limit which should not be exceeded, in order to assure a detonation sensitivity to a common blasting cap.

In the following Tables 8.2 and 8.3 other compositions according to the invention are shown, which have been prepared as formerly described. In all these cases, the alkylamines were salified in situ by organic acids or by TABLE 8.1

Composition No.

Percent by weight:

Water 0.35 0. 40 0. 10 0.40 0. 45 3. 55 0. 90 0. 75 3. 40 4. 50 0. 50 0. 20 Ammonium nitrate" 93. 25 93. 10 88. 75 83. 70 88. 85. 89. 25 87. 00 84. 60 84. 00 85. 00 84. 00 Potassium nitrate. 4. 75 9. 50 4. 75 4. 60 2. 35 4. 75 4. 55 4. 25 7. 0O 9. 50 Barium nitrate 0. 50 0. 50 0. 50 0. 50 0. 5O 0. 48 0. 5O 0. 50 0. 45 0. 45 0. 50 0. 50 Zinc nitrate (6 aq.) 0. l5 0. 50 0. 0. 15 0.30 0. 29 0. 50 0. 50 0. 5O 0. 50 O. 50 Coco amine 0. 0. 25 0. 25 0. 25 O. 50 0. 48 0. 25 0. 25 0. 25 0. 25 0. 25 Tricthanolamine 0. 75 0. 75 0. 75 0. 75 O. 75 0. 75 Dodecylammonium chloride. 0. Fuel oil N0. 4 5. 50 5. 50 5. 50 5. 50 5. 50 5. 50 5. 50 5. 50 5. 50 5. 50 5. 50 5. 50 Explosion characteristics:

Weight strength according to Trauzl (net cm. 00 375 380 370 380 350 375 375 365 350 380 360 Brisance accordin to Hess (with steel plate of double thickness mm 00 15. 5 18. 1 l6. 2 19. 7 14. 5 18. 3 19. 0 15. 8 00 18.2 13. 0 Detonation velocity according to Dautriche (zinc pipe, 30 mm (a) rn./sec O0 3, 950 4, 180 3, 740 4, 360 2, 630 4, 060 3, 880 3, 480 00 4, 080 2, 840 Air gap test on sand, in 22 mm. per length of 175 mm.-cm 0- 2 2 2 2 0- 2 4 6 0 2 0 Air gap test on sand, in 28 mm. per length of 175mm. cm 0 4 4 4 4 0- 6 8 8 O 6 0 Symbols: 00, insensitive to blasting cap No. 6; 0, transmission of detonation when cartridge tips touch each other (gap=0); 0 no transmission of detonation in case of touching cartridges (the primed cartridge explodes completely); 0 no transmission of detonation in case of touching cartridges (the primed cartridge does not go on).

an inorganic acid salt. The use of inorganic free acids was TABLE 83 intentionally avoided. Table 8.3 illustrates some compositions, in the case of which a considerable increase of strength and brisance is obtained through addition of 8514 aluminium powder. In these compositions the aluminium 30 Composition No.

was added to the lipophilic mixed crystals together with 313 &3 212 212 ,2; the fuel 011. 3- g-gg 5 Attention is called to the fact that for all the composi- 'Iriethanolamine 1. trons of Tables 8.1, 8.2 and 8.3 use was made of a tcchm commune 0'35 0. 0.35 cal ammonium nitrate which contained about 0.2% by Ooco-aniine-acetate 0.60 Weight of ammonium sulfate, due to which reason in all i fg fifi fibiggjjj 3:88 :88 3:88 2:88 the preparations of mixed crystals a certain quantity of p gggg c g g g s a barium salt was added. according t o Trauzel All the blasting characteristics shown in Tables 8.2 ggf gg gggga 490 475 and 8.3 were determinated first after storing the cartridges Hess (with steel plate of double thickness) during 3 months at a temperature Of 13 f0 19 a C. m 1g 2 2() 5 19 g 20 2 22. 1 19 g Detonation velocity according to Dautriche (zinc pipe 30 mm. m./see 4, 200 4, 360 4, 150 3, 650 3, 050 3, 720 Air gap test on sand, in

22 mm. per length of 175 mm.-cm 4 4 4 6 6 0 TABLE 8.2 Air gap test on sand, in

28 mm. it per length of Composition No. 175 mm.-cm 6 6 6 8 8 8 While I have disclosed several embodiments of the Percent by weight:

X'ater (h mid t 3.2 .2 .5 2.3 2.3 1 .2 present invention, it 18 to be understood that these emmmonium Ill 1'3. 8 Potassium nitrate 4'00 00 00 7 00 G0 O0 bodiments are given by example only and not in a limiting Barium nitrate 0. a0 0. 30 0. s0 0. 30 sense. Barium perchlorate 0.30 0.30 I claim. Coco-amine--. 0. 20 0. 50 0. 30 0. 20 0.20 n-gotis i mme 0.10 0. 30 .13 0.20 gag 1. A pulverulent or water bearing explosive mixture, .1 o$i;1:::::::::"afar-636;; "6.'i6' 0. 10 Compnsmg Tn'ethanolamine 1. 0 0 to 20% by weight of Water, ii s c i ii (i5g ZQI"III"; 3 to 6% by weight of liquid hydrocarbons, %a t i 1%d 0027)- 50 to 97% by weight of mixed crystals produced by co- 1 F381 3 No 4 4 59 5 0 .0g y ta lization of ammonium mtrate and potassium Expl gs orfitehtaraettelil'istics: d salts 81 S ICIl 36001 B p t T g zif tt a 375 3 5 370 3 5 3 0 375 Said mlied crystllllshhaving a1 crystal lfS ISO- sa acwr Hg 0 morp ous Wit t e monoc inic crysta orm 0 am- Hess (with steel plate ofdouble thickness) filtrate L 18.7 0 said mixed crystals having a lower temperature of crysacpordipg to Daumche tal form transition than 322 'C., which is the normal ei 1 1 03011 111) 4 260 4 060 3 980 4 300 4 190 3 910 lower temperature of transition of pure ammonium Aiggapteston sgandzg ng nitrate mm. 4: per engt o s mmmfimnw u 4 2 2 4 4 2 aid mixedcrystals being crystallized between 100 and Au gap test on l 1 1 2175 20 0., in the presence of salts of primary amino mm. per engt o 6 4 4 6 6 4 gga s having chain lengths ranging from C to C said mixed crystals having a lipophilic surface characteristic, stable at temperatures below 32.2 C. 2. The mixture, as set forth in claim 1, wherein said ratio by weight of ammonium nitrate and potassium salts is from 20/ 1 to 4/1. 3. The mixture, as set forth in claim 1, wherein said salts of primary amino alkanes are in the amount of 0.2 to 1.5% by weight. 4. The mixture, as set forth in claim 1, wherein said mixed crystals have a lipophilic surface characteristic, stable at temperatures between 20 and +20 C. 5. The mixture, as set forth in claim 1, wherein said potassium salt is potassium nitrate. 6. The water bearing explosive mixture, as set forth in claim 1, further comprising an amount of such salts and substances, which are able to depress the saturation temperature of a total hot starting solution down to 60 C., at constant water contents, said depression of saturation temperature decreasing of the solubility of co-dissolved alkylammonium micells, and said decrease of the solubility of said co-dissolved alkylammonium micells increasing the adsorption stability of same on the surface of the mixed crystals, at upper temperatures. 7. The water bearing explosive mixture, as set forth in claim 6, wherein said amount of said salts and substances are from 4 to 8% by weight. 8. The water bearing explosive mixture, as set forth in claim 6, wherein said salts and substances are sodium nitrate. 9. The water bearing explosive mixture, as set forth in claim 6, wherein said salts and substances are calcium nitrate. 10. The water bearing explosive mixture, as set forth in claim 6, wherein said salts and substances are sodiumand calcium nitrate. 11. The water bearing explosive mixture, as set forth in claim 1, further comprising an amount of such substance which is able to increase the solubility of co-dissolved alkylammonium micells at temperatures below 20 C., and said increase of solubility of the co-dissolved alkylammonium micells enhancing the adsorption stability of same on the surface of the mixed crystals, at the lower temperatures. 12. The water bearing explosive mixture, as set forth in claim 11, wherein said amount of said substance is from 5 to 7% by weight. 13. The water bearing explosive mixture, as set forth in claim 11, wherein said substance is formamide. 14. The pulverulent explosive mixture, as set forth in claim 1, wherein said lipophilic mixed crystals are crystallized in the presence of an amount of such substance, which is able to increase the solubility of co-dissolved alkylammonium micells in the low water bearing solution, which wets the dried mixed crystals, at a temperature below 20 C., and said increase of the solubility of the co-dissolved alkylammonium micells enhances the adsorption stability of same on the surface of said mixed crystals, at lower temperatures. 15. The pulverulent explosive mixture, as set forth in claim 13, wherein said amount of said substance is from 1 to 2% by weight. 16. The pulverulent explosive mixture, as set forth in claim 13, wherein said substance is an alkanolammonium salt with 2 or 3 carbon atoms in each alkyl chain.

17. The pulverulent or a water bearing explosive mixture, as set forth in claim 1, further comprising a metallic powder.

18. The pulverulent or a water bearing explosive mixture, as set forth in claim 17, wherein said metallic powder is in the amount of from 0 to 20% by weight.

19. The pulverulent or a water bearing explosive mixture, as set forth in claim 17, wherein said metallic powder is aluminum powder.

20. A process of producing a pulverulent or water bearing explosive mixture with 0 to 20% by weight of water, and an amount of lipophilic mixed crystals which is crystallized out of saturated starting solutions between and 20 C., in the presence of salts of primary amino alkanes having chain lengths ranging from C to C preferably in an amount of 0.2 to 1.5 by weight, and which is sensitized by liquid hydrocarbons in a preferred amount of 3 to 6% by weight, comprising the step of containing in the saturated starting solution potassium salts which are easily soluble in Water, as components of the finished explosive, in order to maintain the lipophilic surface characteristic at lower temperatures, as for instance, 32.2 C., in particular between 20 and +20 C., which has the characteristic of forming with ammonium nitrate, mixed crystals, the crystal form of which is isomorphous with the crystal form of ammonium nitrate III, said mixed crystals having a lower temperature of crystal form transition than 32.2 C., which is the normal lower temperature of transition of pure ammonium nitrate III.

21. The process, as set forth in claim 20, wherein said potassium salts are potassium nitrate.

22. The process, as set forth in claim 20, wherein said potassium salts are in the amount of 3 to 15% by weight.

23. The process of producing a water bearing explosive mixture, as set forth in claim 20, further comprising the step of adding to the saturated hot starting electrolyte solutions such salts or substances which decrease the saturation temperatures of said electrolyte solutions at a constant water content for decreasing the solubility of alkylammonium micells at higher temperatures than 60 C. and for stabilizing micells absorbed on said mixed crystals.

24. The process, as set forth in claim 23, wherein said salts or substances are sodium nitrate.

25. The process, as set forth in claim 23, wherein said salts or substances are calcium nitrate.

26. The process, as set forth in claim 23, wherein said salts or substances are sodium nitrate and calcium nitrate.

27. The process, as set forth in claim 23, wherein said salts or substances are in a quantity of 48% by weight.

28. The process of producing a water bearing explosive mixture, as set forth in claim 20, further comprising adding to the explosive mixture such substances which increase the solubility of the alkylammonium micells at lower temperatures than 20 C. and for stabilizing the micells adsorbed on the mixed crystals.

29. The process, as set forth in claim 28, wherein said substances are formamide.

30. The process, as set forth in claim 28, wherein said substances are in the amount of 5 to 7% by weight.

31. The process of producing a pulverulent explosive mixture, as set forth in claim 20, wherein adding to the hot starting solutions for crystallizing the mixed crystals substances which increase the solubility of alkylammonium micells at lower temperatures than 20 C. and for stabilizing the micells adsorbed on the mixed crystals and which are able to provoke the increase of the solubility of the alkylsaid aluminum powder is used in the amount of 0 to ammonium micells in a water poor final product. 20% by weight.

32. The process, as set forth in claim 30, wherein said substances are alkanol ammonium salts easily References Cited soluble in water, having an alkyl chain length rang- 5 UNITED STATES PATENTS mg from C to C 33. The process, as set forth in claim 30, wherein 3449180 6/1969 Vercauteren 149-46 X saixcileisgtllalistances are 1n an amount of 1 to 2% by CARL D. QUARFORTH, Primary Examiner 34. The process, as set forth in claim 20, further com- 10 LECHERT, Assistant er prising using metallic aluminum powder. 35. The process as set forth in claim 34, wherein 1497, 40, 44, 46, 61 

